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This post documents some testing I did around whether unit tests in Golang are run in parallel. TLDR: Tests in a given package a run serially, unless t.Parallel() is specified. To test this, I created two files in a directory named gotest: $ ls one_test.go two_test.go // one_test.go package main import ( "fmt" "testing" "time" ) func TestOne(t *testing.T) { fmt.Println("1 starts:", time.Now().String()) time.Sleep(5 * time.Second) fmt.Println("1 ends:", time.Now().String()) } // two_test....

Thanks to Julia Evan’s latest post, I learned that creating new slices by sub-slicing an existing slice has an important caveat: They can sometimes use the same backing array! 😬 This is important to understand if you mutate the sub-slice. Take the below example, wherein we accidentally mutate s1! package main import ( "fmt" ) func main() { s1 := []int{0, 1, 2, 3, 4, 5} // len == 6, capacity == 6 s2 := s1[1:5] // len == 4, capacity == 5 // Modifies both s1 and s2, because they share the same backing array....

I run Unifi network gear in my house. As I have multiple wireless access points, I use a controller to manage them so clients can seamlessly roam between them. I run Unifi’s controller software as a Docker container (from here and here) to save myself from running Yet Another Appliance™ and paying for more hardware. I’ve been running v6 for a while, but recently upgraded to v8. These are my notes to myself for how I set this up....

A coworker turned me onto this lovely technique the other day. You can use a git pre-push hook to run all of your Golang unit tests before pushing. To do this, make a the following file: $YOUR_REPO/.git/hooks/pre-push The file must be executable. The file’s contents should be: #!/bin/sh if ! go test ./... ; then echo echo "Rejecting commit. Unit tests failed." echo exit 1 fi Easy peasy.

I wore Invisalign braces from January of 2022 to early 2023. They require a lot of brushing and maintenance while wearing them. Here’s a few things I did along the way which made that easier. 1. Create brushing stations You’re going to brush and floss a lot. (Like a lot.) Anytime you eat or drink anything besides water you must remove the Invisalign trays, brush your teeth and trays, and then floss....

Have you ever been developing on a feature branch and needed to look at a separate branch on the same repo? I have. When this happens, I normally do one of two things: git stash my changes and change branches This is annoying because it’s a lot of steps. I also have to remember which stash to pop when I come back to this branch. Stage all my changes and store them in a work-in-progress commit This is better than #1 but doesn’t let you view both branches simultaneously....

Derek Sivers recently wrote a post explaining how he backups his computers. His post inspired me to improve my own backup strategy and also to write this post. My computer I only have two personal computers whose data I care about; my Macbook Pro and my wife’s Macbook Air. The strategies for backing these up are the same, so I’ll just talk about my computer. It has a lot of important things: files, videos, photos, personal code, and more....

It is often useful to run a subset of the tests in a Go project. You might do this because you only want to see test results for one package or to run tests faster. For these examples, assume your project is a Go module named examplemodule. It has the following structure: examplemodule |_ go.mod |_ go.sum |_ internal |_ foo | |_ foo.go | |_ foo_test.go |_ bar |_ bar....

Today I needed to use the maximum unsigned 64-bit integer value possible in Golang. Here is a short program I wrote with some help from Stack Overflow to help me remember how to calculate these without any dependencies. package main import "fmt" const ( minUint32 = uint32(0) maxUint32 = ^uint32(0) minUint64 = uint64(0) maxUint64 = ^uint64(0) minInt32 = int32(-maxInt32 - 1) maxInt32 = int32(maxUint32 >> 1) minInt64 = int64(-maxInt64 - 1) maxInt64 = int64(maxUint64 >> 1) ) func details[numeric int32 | int64 | uint32 | uint64](name string, num numeric) { fmt....

I learned something new from Julia Evans today. Git has a --fixup argument when committing files which makes it easy to create fixup commits which can get automatically squashed when rebasing. This is fantastic! I’ve known about git commit --amend for years, but this allows you to fixup commits which are several commits back without manually moving a bunch of lines around while interactively rebasing… Let’s assume you have a repo which looks like shown below....